Lord Mandelson warned British car manufacturers not to expect a government bailout, despite the award of a £5m taxpayer loan to van maker LDV.

The business secretary said he would not sanction every request for a bridging loan, after giving £5m to the Birmingham-based firm to help seal a life-saving take-over. "We're not prepared to fork out, carte blanche; cheques to everyone," he said.

LDV was given a week-long stay of execution after a court hearing to place the company into administration was adjourned. LDV's Russian owner, GAZ, said it had reached an agreement in principle to sell its entire shareholding to Malaysian firm Weststar. However, the takeover is at least a week away from being completed.

Mandelson said the Department for Business, Enterprise and Regulatory Reform made an exception for LDV because "somebody" needed to step in to facilitate the takeover. He added: "It would not have been responsible to ignore that request but these are very close calls."

LDV refused to guarantee the future of the 850 workers employed at the company's Washwood Heath plant. LDV spokesman Guy Jones said: "This deal will secure production in Birmingham, at this site, securing as many jobs as possible, but clearly the marketplace and the economy is going to determine exactly how many people are required to build vehicles and assemble them."

GAZ, controlled by Russian billionaire Oleg Deripaska, has confirmed it is in talks to bid for a stake in troubled carmaker Opel. A spokesman for GAZ told the German economic daily Handelsblatt that the debt-laden Russian company was examining the invitation before making a decision. The announcement considerably heightens the bidding war for the German company.

The spokesman stressed any involvement in Opel by GAZ would not require it to pay for a stake in the company. Rather, GAZ would provide production facilities for the manufacture of new models in Russia and take over service and sales facilities in former Soviet countries.

The first official confirmation by GAZ that it was involved in the talks came a day after the Canadian-Austrian auto parts maker Magna, a GAZ partner, publicly announced its interest in Opel.

Magna owner Frank Stronach said on Tuesday his company was interested in a stake of up to 20% in Opel. Magna is reported to be planning a joint bid with GAZ and the Russian state-owned Sberbank.The GAZ spokesman gave no further details about its bid, which critics said was unfeasible because of its indebted status.

The company is effectively bankrupt and has sharply reduced its production in recent weeks. It specialises in manufacturing small transport vehicles. But its attempts to produce new passenger cars for the traditional Russian brand Volga, were considered a flop.

Experts said one advantage to Opel of joining up with GAZ and the state-owned Russian bank Sperbank, would be the access it would gain to the developing market in Russia.

A unit of troubled US car maker General Motors (GM), Opel's fate is in the balance. GM has until May 28 to agree on a rescue plan with its US creditors or it faces insolvency. Bids for Opel have to be submitted by then.

Karl-Theodor zu Guttenberg, Germany's economics minister appealed on Tuesday for a swift resolution. "The decision should not be put off indefinitely," he said.